Users access a wide variety of web sites over the Internet. In general, the web server receiving a request has little or no knowledge about the user, and thus the response must be made generically. In some instances, a user explicitly provides information, such as responding to online questions. Usage of user-provided information is subject to error, and is burdensome to users. In other instances, information about a user is collected over time based on previous activity.
However, even with some information about a user, a web server typically has little information about the user's computer.